Elements of PHP functions: detailed explanation

The components of a PHP function: function name, parameter list, function body. The function name is used to call the function, the parameter list contains the parameters received, and the function body places the code to be executed. In practice, a summation function can be created to return the result of adding two numbers. Function names cannot be the same, parameter types can be specified through hints, the function body can contain any PHP syntax and can return any type of value.

Element composition of PHP function

Syntax format

function 函数名称(参数列表) {
    函数体；
}

Element composition

• #Function name: Identifier of the function, used to call the function in the program.
• Parameter list: Contains the parameters received by the function, separated by commas. Can be optional or default parameters.
• Function body: Place the code block to be executed, and you can use the return statement to return the result.

Practical case

Create a function that finds the sum of two numbers:

function sum($num1, $num2) {
    return $num1 + $num2;
}

// 用法
$result = sum(5, 10);
echo $result; // 输出：15

Type description

• The function name cannot have the same name as a reserved word or an existing function.
• The types in the parameter list are not specified in the function definition, but the expected type can be specified through parameter type hints.
• The function body can use any PHP syntax, including control structures, loops, and variable operations.
• A function can return a value of any type, or be declared to not return a value using the void keyword.

Other notes

• Parameters can be passed by value or by reference.
• A function can be declared as a static function through the static keyword, which will not be instantiated.
• Function can be public, protected or private to control its visibility.

The above is the detailed content of Elements of PHP functions: detailed explanation. For more information, please follow other related articles on the PHP Chinese website!